There are unauthorized sites that have displayed ads using your AdSense publisher ID within the last week. Please click here to view them. Unauthorized Sites: www.facebook.com Im using only two ads but there are 5 more activated at adsense manager
well on adsense there is a setting called "Allowed Site" . You can use them to avoid others using your ads . also facebook might be using because you have some application for the facebook
In AdSense account, go to My Account -> Account Access then click disable access if there is a link of Facebook. If not, immediately mail to google and inform them the situation otherwise you will be banned.
Im using adsense setting already for many months. I have added only my site.. but its showing unauthorized use of ads. & in list it show facebook. com .rofl. let me post a screenshot alright. here are my screenshots.. Im using two ads & they are in blue but I dont know where are others being used.. and this is screenshot of allowed site..
If you added only your site/sites in allowed site and other site / sites are using you ID, there is no problem for you, ads could be shown at non-allowed sites, but clicks and impressions will not be count,
well like digg or blogcatalog you bookmark some post there, and users came to your site through digg or some bookmarking site, they show their own url redirected to you, then its show that digg is showing your ads. i think this is something like this!!!!